It is a matter of regrettable fact that the number of accidents associated with the use of ladders is still too high resulting in serious and in some instances fatal injuries. In most if not all instances, the reason for such accidents is inadequate anchoring of the ladder when being in position angled against a wall or similar structure. Many and varied arrangements have been proposed for stabilizing the ladder in its use position. For example, legs attached to the stiles of the ladder have been suggested for additional contact with the ground to give more stability and struts for contact with the supporting wall have also been proposed.
To this end, the safety demands for entering into a pit of an elevator shaft have been intensified as this is to be read in the EN 81-20 regulations. So, the maximum weight of the ladder shall not exceed 15 kg in order to allow its easy and safe handling from the landing sill (some national regulations may even request a maximum weight less than 15 kg for manual handling) and the safe use of the ladder in its position of use shall be ensured by means of a device securing the ladder to the landing sill, or the bottom of the pit, or the wall of the well. At least, the risk of a person tipping over of the ladder when standing or grasping the upper part of the ladder above a landing sill level shall be prevented by means of appropriate measures.
From a technical point of view, it is critical to minimize the impact of these requirements for a layout design of standard elevators. A more specific type of ladder support for ladders intended for a use in pits finds form in a bracket attachable at the ladder with a clamp for positive engagement with for example a wall or landing level of an elevator shaft. In use the ladder is anchored at its top end to the floor edge, thus assisting in the prevention of inadvertent slippage away from the intended orientation of the ladder against the wall of the shaft. One such bracket for a modular ladder with an adjustable sill hook profile is described in EP 1 609 943. A locking device is provided at the sill hook profile being parallel adjustable to a longitudinal axis of the ladder rail being therewith fastened over a support or directly over a pit level.
An additional request would be the ease of installation and use during the installation and maintenance. The future usage of this invention would be all elevators requiring a pit ladder.